Halogen floodlight SMT reflow

This project was waiting on a box fot two years, until I had to solder 100 PCBs. After some research on SMD/SMT reflow oven hacking, I was confident to build my own reflow device with an halogen floodlight.

Valentia Case-Rap foldable 3D printer

In the summer of 2016, browsing in Thingiverse I came across the Case-Rap 1.0 foldable 3D printer by jlguils. I liked the design strategy of dividing the structure in parts that, when folded, transformed themselves into a portable case. And started to develop my own custom version: the Valentia Case-Rap foldable 3D printer.

Mysterious z ribbing with PLA... solved!

I've been having consistent z ribbing on different custom printers since a year or so...
No matter what I've tried (z wobble isolator, z axis strabilizer, threaded rod diameter/pitch changed, etc.).
Yesterday my heated bed's MOSFET failed while printing yet another calibration cube and guess what... NO Z RIBBING!!!

Arduvision (II): OV7670 + FIFO module and arduino Mega

After several people asking for instructions to use an Arduino Mega to interface the ov7670 sensor, I decided to publish a tutorial about it...

Simple passive mono/stereo to stereo audio mixer circuit

A while ago I needed a very simple pasive miker to join one stereo and two mono signals together before amplifying them...

There is some mixed information on how to properly connect a mono signal to a stereo input, but most of it uses active mixing.

Repair faulty HC-SR04 ultrasonic sensor (solve erratic no-readings problems)

Recently I got some of these cheap sensors from Chinese suppliers, for a workshop I had to teach.

A couple of students reported that their sensors were behaving in an erratic way, sometimes working, then stopping again, the working...

After replacing them with more expensive ones bought at a local store, I decided to try fixing the faulty ones...

DIY PCBs on the cheap: toner transfer with Box Packing Tape and a Hair Straightener / Iron

A few months ago I started to design an affordable 2WD Robot Kit to teach 20 students in a workshop in the AVM Master, at the Universidad Politécnica de Valencia, Spain.

That means also making about 100 tiny PCBs!